h<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<title>My web site</title>
		<style type="text/css">
			body{
				margin: 0;
				padding: 0;
				
			}
			.box{
				height: 500px;
				background: #aaa;
				position: relative;
			}
			.nav{
				width: 960px;
				height: 60px;
				background: #666;
				position: absolute;
				bottom: 0;
				left: 50%;
				margin-left: -480px;
			}
		</style>
	</head>
	<body>
		<div class="box">
			<div class="nav"></div>
		</div>
	</body>
</html>